In a major policy change, the Health and Welfare Ministry plans to support water fluorination to help prevent tooth decay nationwide, ministry officials said.
The ministry will give local governments technical support for adding fluorine to public water supplies and for setting and maintaining its standard concentration of 0.8 ppm or less, they said.
Fluorine is considered effective in preventing tooth decay and is used in the public water of 38 countries, including the United States, Canada and Australia. In Japan, the fluorine level is less than 0.1 ppm.
The government had previously opposed fluorinating public water because many residents whose teeth were stained by naturally high fluorine levels in the water supply had sued local authorities.
However, the government has reversed its stance because the effectiveness of fluorine in strengthening teeth and repairing tooth decay has been scientifically proven.
Dentists and local government officials say adding fluorine to public water is the best method for preventing cavities because it is easy, effective and inexpensive.
The Okinawan village of Gushikawa proposed the nation's first pilot program for fluorinating public water in August and has asked the ministry for financial support.